A writer can demonstrate correct comma usage by placing commas after introductory adverbs, placing commas before coordinating conjunctions that link two independent clauses, and placing commas after dependent clauses that begin sentences. Commas are also used in dates, addresses, dialogue, lists, and in many other instances.
Commas are also used to separate adjectives that modify the same noun. For example: "The fresh, juicy orange was delicious." Commas are used to offset negation in a sentence. For example: "Turn left, not right." In most cases, commas are used before every sequence of three numbers in numbers with four or more digits. For example: "I drove over 1,500 miles last month." There are also many other examples of proper comma usage.